Complexes (Me2GeGeMe2)[η5-C5R4)Fe(CO)]2(u-CO)2(R=H, 1; Me, 3) 1 and 3, prepared by the reaction of C5R4HMe2GeGeMe2C5R4H with Fe(CO)5 in refluxing xylene, underwent a novel thermal reaction between their Ge-Ge and Fe-Fe bonds, forming corresponding rearrangement products with new cyclic structures, [Me2Ge(η5-C5R4)Fe(CO)2]2(R=H, 2; Me 4). Compared with the case of silicon, the weaker Ge-Ge bond resulted in an easier rearrangement reaction. Reactions of 1 with indine and sodium amalgam were examined. Molecular structures of 1, 2, 3, and 4 were determined by X-ray diffraction.

The ansa-metallocene complexes Me2Ge(η5-C5Me4)2MCI2[M=Ti(1), Zr(2)], Me2Ge(η5-C5H3Bu-t)2ZrCl2(3) and Me2Ge(η5-C5H4)(η5-C5H3R)ZrCl2[R=Me(4), t-Bu (5)] were prepared by the reaction of the corresponding ligands with n-BuLi and MCl4 2THF, respectively. The molecular structures of 1 and 2 have benn determinde by the X-ray diffraction method. Complexe 2-5 in combination with MAO were studied as catalysts for ethylene polymerizatiion and all the germyl-bridged zirconocene catalysts show high activities at relative high temperatures. This indicates that the germyl-bridged zirconocene systems show thermally stable catalyst sysstems for polymerization of ethylene.

The binuclear ruthenium complex (Me2-SiSiMe2)[(η5-C5H4)Ru(CO)]2(μ-CO)2(3) was obtained in poor yield by reaction of Ru3(CO)12 with C5H5Me2-SiSiMe2C5H5 in boiling heptane. A thermal rearrange-ment reaction of 3 in heptane afforded the complex [(Me2Si)(η5-C5H4)Ru(CO)2]2 (4), which was evidently formed via a metathesis between Si-Si and Ru-Ru bonds in 3. Molecular structures of 3 and 4 have been determined by X-ray diffraction.

A series of doubly bridged bis(cyclopentadienyl) tetracarbonyl diiron complexes (7-13) have been synthesized by the reaction of the corresponding ligand (1-6) with Fe(CO)5 in refluxing xylene. It is unusual that the reaction of ligand (GeMe2)(GeMe2)(C5H4)2 (3) with Fe(CO)5 gave the complex (GeMe2)[η5-C5H4)Fe(CO)]2(μ-CO)2 (10) as the main product which lost the GeMe2, only a small amount of the expected product (GeMe2)2[(η5-C5H3)Fe(CO)]2(μ-CO)2 (9) was obtained. The molecular structures of 9 and (SiMe2SiMe2)2[(η5-C5H3)Fe(CO)]2(μ-CO)2 (13) have been determined by X-ray diffraction.